Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/004—Photosensitive materials
  • G03F7/09—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers
  • G03F7/11—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers having cover layers or intermediate layers, e.g. subbing layers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F212/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
  • C08F212/02—Monomers containing only one unsaturated aliphatic radical
  • C08F212/04—Monomers containing only one unsaturated aliphatic radical containing one ring
  • C08F212/06—Hydrocarbons
  • C08F212/12—Monomers containing a branched unsaturated aliphatic radical or a ring substituted by an alkyl radical
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F212/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
  • C08F212/02—Monomers containing only one unsaturated aliphatic radical
  • C08F212/04—Monomers containing only one unsaturated aliphatic radical containing one ring
  • C08F212/14—Monomers containing only one unsaturated aliphatic radical containing one ring substituted by heteroatoms or groups containing heteroatoms
  • C08F212/22—Oxygen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
  • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F220/10—Esters
  • C08F220/22—Esters containing halogen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
  • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F220/10—Esters
  • C08F220/34—Esters containing nitrogen, e.g. N,N-dimethylaminoethyl (meth)acrylate
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D125/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Coating compositions based on derivatives of such polymers
  • C09D125/02—Homopolymers or copolymers of hydrocarbons
  • C09D125/16—Homopolymers or copolymers of alkyl-substituted styrenes
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D133/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Coating compositions based on derivatives of such polymers
  • C09D133/02—Homopolymers or copolymers of acids; Metal or ammonium salts thereof
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/004—Photosensitive materials
  • G03F7/09—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers
  • G03F7/091—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers characterised by antireflection means or light filtering or absorbing means, e.g. anti-halation, contrast enhancement
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/16—Coating processes; Apparatus therefor
  • G03F7/168—Finishing the coated layer, e.g. drying, baking, soaking
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/20—Exposure; Apparatus therefor
  • G03F7/2002—Exposure; Apparatus therefor with visible light or UV light, through an original having an opaque pattern on a transparent support, e.g. film printing, projection printing; by reflection of visible or UV light from an original such as a printed image
  • G03F7/2004—Exposure; Apparatus therefor with visible light or UV light, through an original having an opaque pattern on a transparent support, e.g. film printing, projection printing; by reflection of visible or UV light from an original such as a printed image characterised by the use of a particular light source, e.g. fluorescent lamps or deep UV light
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/26—Processing photosensitive materials; Apparatus therefor
  • G03F7/30—Imagewise removal using liquid means
  • G03F7/32—Liquid compositions therefor, e.g. developers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/027—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34
  • H01L21/0271—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising organic layers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
  • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F220/04—Acids; Metal salts or ammonium salts thereof
  • C08F220/06—Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof

Definitions

• the present invention relates to a resist overlayer film forming composition for lithography that is used in a process of producing a semiconductor device using photolithography and is effective in reducing adverse effects caused by exposure light and yielding a good resist pattern, a method for forming a resist pattern using the resist overlayer film forming composition for lithography, and a method for producing a semiconductor device using the forming method.
• microfabrication using photolithography techniques has conventionally been performed in production of semiconductor devices.
• the microfabrication is a process of forming a thin film of a photoresist composition on a substrate to be processed such as a silicon wafer, applying active light such as ultraviolet rays thereon through a mask pattern having semiconductor device patterns, developing the pattern, and etching the substrate to be processed such as a silicon wafer using the resulting photoresist pattern as a protection film (mask).
• the active light to be used has been changed to those at shorter wavelengths, for example, from KrF excimer laser (wavelength of 248 nm) to ArF excimer laser (wavelength of 193 nm).
• BARC Bottom Anti-Reflective Coating
• the anti-reflective coatings include: inorganic anti-reflective coatings including, for example, titanium, titanium dioxide, titanium nitride, chromium oxide, carbon, and ⁇ -silicon; and organic anti-reflective coatings made from a light absorbing substance and a polymer compound.
• inorganic anti-reflective coatings including, for example, titanium, titanium dioxide, titanium nitride, chromium oxide, carbon, and ⁇ -silicon
• organic anti-reflective coatings made from a light absorbing substance and a polymer compound.
• the former requires systems for forming coatings such as a vacuum deposition system, a CVD system, and a sputtering system, whereas the latter requires no special system.
• organic anti-reflective coatings are advantageous and have been elaborately examined.
• ArF immersion lithography in which exposure is performed through water has been practiced as a next-generation photolithography technique that replaces the photolithography technique using ArF excimer laser (wavelength of 193 nm).
• the photolithography techniques using light have been approaching their limits.
• EUV lithography technique using EUV at a wavelength of 13.5 nm
• a substrate covered with an EUV resist is exposed by EUV radiation and developed with a developer to form a resist pattern.
• An overlayer on an EUV resist which includes a polymer including a group containing one or more of beryllium, boron, carbon, silicon, zirconium, niobium, and molybdenum in order to protect the EUV resist from contaminants and to block undesirable radiation, for example, UV and DUV (Out of Band/out-of-band radiation, OOB) (Patent Document 1, Patent Document 2).
• Non Patent Document 1 a topcoat formed of a polyhydroxystyrene (PHS)-based compound, an acrylic compound, or other substances is applied to an overlayer on an EUV resist to reduce OOB
• Non Patent Document 2 a film of an EUV resolution enhancement layer is applied to an overlayer on an EUV resist to absorb OOB and improve the EUV resist resolution
• PHS polyhydroxystyrene
• Patent Document 3 A novolac-based material including a naphthalene ring is described as a resist overlayer film forming composition for EUV lithography
• a resist protecting film material including an acrylic polymer including a hexafluoroisopropyl alcohol group Patent Document 4
• a resist protecting film material including an ester compound having a fluoroalkyl group as a solvent Patent Document 5
• a photoresist overlayer film forming composition including a solvent having an ether structure Patent Document 6
• a topcoat material including a hexafluoroalcohol unit and an alcohol-based solvent which can be used as a topcoat for immersion process or a top anti-reflective coating (TARC) to be applied on the top surface of a photoresist
• a resist protecting film material which includes a polymer compound prepared by copolymerizing a repeating unit having a carboxy group and/or a sulfo group and a repeating unit including a hydrocarbon (Patent Document 8).
• a method for forming a resist pattern is described, in which a polymer includes not less than 50 mol % of a unit structure including at least one of aromatic groups and heteroaromatic groups (Patent Document 9).
• UV light and DUV light are emitted together with EUV light from EUV light to emit.
• the EUV light includes about 5% of light having wavelengths of 300 nm or lower in addition to EUV light.
• the wavelength range from 180 nm to 300 nm, in particular, 180 nm to 260 nm or so has the highest intensity, leading to lower sensitivity of EUV resists and degradation in pattern shape.
• line widths of 22 nm or smaller the effects of such UV light and DUV light (OUT of BAND/out-of-band radiation. OOB) appear to adversely affect the resolution of EUV resists.
• a filter may be installed in a lithography system, but this method makes the process complicated.
• the present invention is made to provide an optimum resist overlayer film forming composition to solve these problems.
• a resist overlayer film forming composition for use in a lithography process in semiconductor device production is provided, in which the composition, as a resist overlayer film, in particular, as an overlayer film for an EUV resist, does not intermix with a resist, blocks undesirable exposure light particularly in EUV exposure, for example, UV and DUV and selectively transmits EUV alone, is excellent at blocking gas escaped from the resist, can be developed with a developer after exposure, and is applicable to either a positive resist or a negative resist.
• the present invention is as follows.
• a resist overlayer film forming composition comprising a polymer (P) including unit structures of Formula (1) and Formula (2) and having a weight average molecular weight, measured by gel permeation chromatography, of 500 to 2,000, and a C 8-16 ether compound as a solvent.
• R 1 and R 2 are the same or different and are each a hydrogen atom or a C 1-10 alkyl group
• Q 2 and Q 2 are the same or different and are each a single bond, an ester bond (—C( ⁇ O)—O— or —O—C( ⁇ O)—), or an amide bond (—NH—CO— or —CO—NH—):
• X 2 is a single bond, a C 1-6 alkylene group, or a C 6-14 arylene group;
• R 1a is a C 1-10 alkyl group
• n1 is an integer of 1 to 3; and m1 is an integer of 0 to 2.
• R 3 is a hydrogen atom or a C 1-10 alkyl group
• Q 3 is a single bond, an ester bond (—C( ⁇ O)—O— or —O—C( ⁇ O)—), or an amide bond (—NH—CO— or —CO—NH—);
• X 3 is a single bond, a C 1-6 alkylene group, or a C 6-14 arylene group; and R 3a s are the same or different and are each a hydrogen atom, a C 1-10 alkyl group, or a C 1-4 acyl group.
• R 4 is a hydrogen atom or a C 1-10 alkyl group
• Q 4 is a single bond, an ester bond (—C( ⁇ O)—O— or —O—C( ⁇ O)—), or an amide bond (—NH—CO— or —CO—NH—);
• R 4a is a C 1-10 alkyl group in which some or all of hydrogen atoms are optionally substituted with fluorine atoms, or a C 6-14 aryl group in which some or all of hydrogen atoms are optionally substituted with the alkyl groups.
• W 1 and W 2 are the same or different and are each a hydrogen atom, a fluorine atom, a trifluoromethyl group, a difluoromethyl group, or a monofluoromethyl group: three w 3 s are each independently a hydrogen atom, a fluorine atom, or a combination of the hydrogen atom and the fluorine atom; at least one of W 1 , W 2 , and w 3 , is a trifluoromethyl group, a difluoromethyl group, a monofluoromethyl group, or a fluorine atom; m2 is an integer of 0 to 9; and the maximum number of carbon atoms included in Formula (5) is 10.]
• composition according to [8], wherein the acid compound is a sulfonic acid compound or a sulfonic acid ester compound.
• composition according to [8], wherein the acid compound is an onium salt-based acid generator, a halogen-containing compound-based acid generator, or a sulfonic acid-based acid generator.
• composition according to any one of [1] to [10], further comprising a basic compound comprising a basic compound.
• composition according to any one of [1] to [11], wherein a resist to be used with the composition is a resist for EUV (wavelength of 13.5 nm).
• a method for producing a semiconductor device comprising: forming a resist film on a substrate; applying the resist overlayer film forming composition according to any one of [1] to [11] on the resist film and baking the composition to form a resist overlayer film; exposing the semiconductor substrate covered with the resist overlayer film and the resist film; and performing development after exposure to remove the resist overlayer film and the resist film.
• a method for forming a resist pattern for use in production of a semiconductor device comprising applying the resist overlayer film forming composition according to any one of [1] to [11] on a resist film formed on a semiconductor substrate and baking the composition to form a resist overlayer film.
• the present invention relates to a composition for forming a resist overlayer film, which, as a resist overlayer film forming composition, in particular, as an overlayer film forming composition for an EUV resist, forms a resist overlayer film that does not intermix with an EUV resist, blocks undesirable exposure light particularly in EUV exposure, for example, UV and DUV and selectively transmits EUV alone, and can be developed with a developer after exposure.
• a resist overlayer film forming composition in particular, as an overlayer film forming composition for an EUV resist
• forms a resist overlayer film that does not intermix with an EUV resist blocks undesirable exposure light particularly in EUV exposure, for example, UV and DUV and selectively transmits EUV alone, and can be developed with a developer after exposure.
• composition according to the present invention contains an aromatic hydrocarbon ring that can absorb undesirable OOB of 180 am to 260 nm in DUV light included in EUV exposure light to improve the resolution of the EUV resist.
• a resist overlayer film having strong absorption in the vicinity of 200 nm can be formed.
• This resist overlayer film has the effect of suppressing excessive activation of a photo acid generator (PAG) present in the underlying resist, in addition to the absorption of OOB.
• PAG photo acid generator
• This effect can suppress degradation of the resist pattern (for example, increase of the value of Line Width Roughness (LWR)) due to the excessive activation of the photo acid generator.
• this effect is high when a triphenylsulfonium-based photo acid generator is present in the resist for EUV.
• the resist overlayer film formed of the composition according to the present invention is excellent at blocking gas escaping from the resist, in particular, during EUV exposure and thus can prevent contamination of the exposure system by the escaping gas components.
• the resist overlayer film forming composition according to the present invention includes a solvent having low solubility for a resist resin, that is, a solvent of C 8-16 having an ether bond (hereinafter also called ether-based solvent) and thus can be applied to a variety of resists, irrespective of resist types (positive or negative).
• a solvent having low solubility for a resist resin that is, a solvent of C 8-16 having an ether bond (hereinafter also called ether-based solvent) and thus can be applied to a variety of resists, irrespective of resist types (positive or negative).
• the polymer (P) to be used in the present invention includes a carboxy group according to the unit structure of Formula (2) and thus, in the case of general positive resists, can be dissolved with the resist in an alkaline developer during development after exposure. In this case, the composition including the polymer (P) can be dissolved away by an alkaline developer.
• Such a development process for positive resists is called positive tone development (PTD).
• the polymer (P) to be used in the present invention can be dissolved in a development solvent (butyl acetate, 2-heptanone, or the like) to be used in a development process for general negative resists. Therefore, the composition including the polymer (P) can be dissolved away by the developer.
• a development process for negative resists is called negative tone development (NTD).
• the resist overlayer film forming composition according to the present invention comprises a polymer (P) including unit structures of Formula (1) and Formula (2) described later and having a weight average molecular weight, measured by gel permeation chromatography (GPC), of 500 to 2,000, and a C 8-16 ether compound as a solvent.
• P polymer
• GPC gel permeation chromatography
• the resist overlayer film forming composition according to the present invention is mainly characterized by comprising a polymer (P) including unit structures of Formula (1) and Formula (2) and having a weight average molecular weight, measured by gel permeation chromatography, of 500 to 2,000, and a C 8-16 ether compound as a solvent.
• R 1 and R 2 are the same or different and are each a hydrogen atom or a C 1-10 alkyl group
• Q 1 and Q 2 are the same or different and are each a single bond, an ester bond (—C( ⁇ O)—O— or —O—C( ⁇ O)—) or an amide bond (—NH—CO— or —CO—NH—);
• X 2 is a single bond, a C 1-6 alkylene group, or a C 6-14 arylene group;
• R 1a is a C 1-10 alkyl group
• n1 is an integer of 1 to 3; and m1 is an integer of 0 to 2.
• the molar ratio of the unit structures of Formula (1) and Formula (2) to the entire polymer (P) is preferably
• the aromatic group in Formula (1) absorbs DUV light included in the EUV exposure light.
• the presence of R 1a improves the solubility in an ether-based solvent.
• the carboxy group of Formula (2) is added in order to make the polymer (P) soluble in the alkaline aqueous solution when an alkaline aqueous solution is used in development after exposure of the resist.
• Examples of the C 1-10 alkyl group include methyl group, ethyl group, n-propyl group, i-propyl group, cyclopropyl group, n-butyl group, i-butyl group, s-butyl group, t-butyl group, cyclobutyl group, 1-methyl-cyclopropyl group, 2-methyl-cyclopropyl group, n-pentyl group, 1-methyl-n-butyl group, 2-methyl-n-butyl group, 3-methyl-n-butyl group, 1,1-dimethyl-n-propyl group, 1,2-dimethyl-n-propyl group, 2,2-dimethyl-n-propyl group, 1-ethyl-n-propyl group, 1,1-diethyl-n-propyl group, cyclopentyl group, 1-methyl-cyclobutyl group, 2-methyl-cyclobutyl group, 3-methyl-cyclobutyl group, 1,2-d
• Examples of the C 1-6 alkylene group include methylene group, ethylene group, n-propylene group, isopropylene group, cyclopropylene group, n-butylene group, isobutylene group, s-butylene group, t-butylene group, cyclobutylene group, 1-methyl-cyclopropylene group, 2-methyl-cyclopropylene group, n-pentylene group, 1-methyl-n-butylene group, 2-methyl-n-butylene group, 3-methyl-n-butylene group, 1,1-dimethyl-n-propylene group, 1,2-dimethyl-n-propylene group, 2,2-dimethyl-n-propylene group, 1-ethyl-n-propylene group, cyclopentylene group, 1-methyl-cyclobutylene group, 2-methyl-cyclobutylene group, 3-methyl-cyclobutylene group, 1,2-dimethyl-cyclopropylene group, 2,3-dimethyl-cyclo
• Examples of the C 6-14 arylene group include phenylene group, naphthylene group, anthracenylene group, and biphenylene group.
• Q 1 and Q 2 are preferably the same or different and are each a single bond or an ester bond (—C( ⁇ O)—O— or —O—C( ⁇ O)—).
• R 1 and R 2 are preferably selected from a hydrogen atom, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, t-butyl group, and 1,1-diethyl-n-propyl group, more preferably selected from a hydrogen atom, methyl group, and ethyl group.
• X 2 is preferably a single bond, a methylene group, an ethylene group, an n-propylene group, an n-butylene group, a phenylene group, or a biphenylene group.
• R 1a is preferably methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, t-butyl group, n-pentyl group, n-hexyl group, 1-methyl n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decanyl group, 1,1-diethyl-n-propyl group, 2-methyl-n-propyl group, or 2,2′-dimethyl-n-propyl group.
• m1 is preferably 0, in terms of preventing excessive activation of the photo acid generator present in the resist to form a satisfactory resist pattern, for the foregoing reason, and in terms of production costs of the polymer (P).
• the solvent used in the composition according to the present invention is a C 8-16 ether compound (ether-based solvent).
• a solvent of C 8-16 having an ether bond is preferably used as a solvent included in the resist overlayer film forming composition in order to prevent intermixing with the EUV resist (mixing of the layers).
• the ether-based solvent has low solubility for a resin that forms a resist, irrespective of the kinds of resin (for example, methacrylate-based resins, PHS-based resins, hybrids containing both of methacrylate and hydroxystyrene (HS)).
• resin for example, methacrylate-based resins, PHS-based resins, hybrids containing both of methacrylate and hydroxystyrene (HS)
• the C 8-16 ether compound (ether-based solvent) as a solvent used in the composition according to the present invention is a compound of Formula (6).
• a 1 and A 2 are each independent and an optionally substituted linear, branched, or cyclic saturated alkyl group having a carbon atom number of 1 to 15.
• Examples of the linear, branched, or cyclic saturated alkyl group having a carbon atom number of 1 to 15 include methyl group, ethyl group, n-propyl group, i-propyl group, cyclopropyl group, n-butyl group, i-butyl group, s-butyl group, t-butyl group, cyclobutyl group, 1-methyl-cyclopropyl group, 2-methyl-cyclopropyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decanyl group, n-undecanyl group, n-dodecanyl group, n-tridecanyl group, n-tetradecanyl group, n-pentadecanyl group, 1-methyl-n-butyl group, 2-methyl-n-butyl group,
• examples of preferred solvents include dibutyl ether, diisobutyl ether, di-tert-butyl ether, dipentyl ether, diisoamyl ether, dihexyl ether, dioctyl ether, and cyclopentyl methyl ether, which have a good balance between the solubility of the polymer (P) and the insolubility of the resist.
• Further preferable solvents are dibutyl ether, diisobutyl ether, and diisoamyl ether, and a particularly preferable solvent is diisoamyl ether. These ether-based solvents can be used singly or in the form of a mixture.
• the proportion of the ether solvent in the solvent in the composition according to the present invention is preferably 100% by mass, but may be 90% by mass or more to 100% by mass, or may be 87% by mass or more to 100% by mass.
• an alcohol-based solvent below or water may be mixed, if necessary.
• saturated alkyl alcohols include 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 1-heptanol, 2-heptanol, tert-amyl alcohol, neopentyl alcohol, 2-methyl-1-propanol, 2-methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-diethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol,
• aromatic alcohols examples include 1-phenylpropanol, 2-phenylpropanol, 3-phenylpropanol, 2-phenoxyethanol, phenethyl alcohol, and styralyl alcohol.
• Those alcohol-based solvents or water may be used singly or in combination of two or more of them.
• the ratio of the other solvents above to be added is 0.01% to 13% by mass to the ether-based solvent.
• organic solvents may be mixed together with the ether-based solvent.
• the solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxyprop
• the polymer (P) preferably includes a unit structure of Formula (3), if necessary, in addition to Formula (1) and Formula (2).
• R 3 is a hydrogen atom or a C 1-10 alkyl group
• Q 3 is a single bond, an ester bond (—C( ⁇ O)—O— or —O—C( ⁇ O)—), or an amide bond (—NH—CO— or —CO—NH—);
• X 3 is a single bond, a C 1-6 alkylene group, or a C 6-14 arylene group;
• R 3a s are the same or different and are each a hydrogen atom, a C 1-10 alkyl group, or a C 1-4 acyl group.
• Examples of the C 1-10 alkyl group include the alkyl groups listed above.
• Examples of the C 1-6 alkylene group include the alkylene groups listed above.
• Examples of the C 6-14 arylene group include the arylene groups listed above.
• Examples of the C 1-4 acyl group include methanoyl group, ethanoyl group, propanoyl group, and butanoyl group.
• R 3 is preferably a hydrogen atom, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, or t-butyl group, particularly preferably a hydrogen atom, methyl group, or ethyl group.
• Q 3 is preferably a single bond or an ester bond (—C( ⁇ O)—O— or —O—C( ⁇ O)—).
• X 3 is preferably a single bond, a methylene group, an ethylene group, an n-propylene group, or an n-butylene group.
• R 3a is preferably a combination selected from a hydrogen atom, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, t-butyl group, 1-methyl-n-butyl group, 2-methyl-n-butyl group, and 3-methyl-n-butyl group, 1-methyl-n-propyl group, 2-methyl-n-propyl group, methanoyl group, and ethanoyl group.
• the polymer (P) having the unit structure of Formula (3) can adjust the shape of the resist by the property of basicity of its side chain. More specifically, the interaction with the acid present in the resist underlying the composition according to the present invention enables the resist shape after exposure and development to be controlled (the resist shape after exposure and development is preferably rectangular).
• the composition according to the present invention comprising the polymer (P) including the unit structure of Formula (3) can be used as it is, without subsequently adding a basic compound to be described later, to control the resist shape well. However, a basic compound may be further included, if necessary, in the composition including the polymer (P) having the unit structure of Formula (3).
• the molar ratio of the unit structure of Formula (3) to the entire polymer (P) therefore need not be high, and is 0.1 to 50 mol % with respect to the entire polymer (P), further preferably 0.1 to 30 mol %, further preferably 0.1 to 20 mol %, further preferably 0.1 to 10 mol %.
• the polymer (P) preferably includes a unit structure of Formula (4), if necessary, in addition to Formula (1) and Formula (2).
• R 4 is a hydrogen atom or a C 1-10 alkyl group
• Q 4 is a single bond, an ester bond (—C( ⁇ O)—O— or —O—C( ⁇ O)—), or an amide bond (—NH—CO— or —CO—NH—);
• R 4a is a C 1-10 alkyl group in which some or all of hydrogen atoms are optionally substituted with fluorine atoms, or a C 6-14 aryl group in which some or all of hydrogen atoms are optionally substituted with the alkyl groups.
• the alkyl group refers to “a C 1-10 alkyl group in which some or all of hydrogen atoms are optionally substituted with fluorine atoms”.
• Examples of the C 1-10 alkyl group include the alkyl groups listed above, and some or all of hydrogen atoms of the alkyl group are optionally substituted with fluorine atoms.
• Examples of the C 6-14 aryl group include phenyl group, benzyl group, naphthyl group, anthracenyl group, and biphenyl group.
• R 4 is preferably a hydrogen atom, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, or t-butyl group, particularly preferably, a hydrogen atom, methyl group, or ethyl group.
• Q 4 is preferably a single bond or an ester bond (—C( ⁇ O)—O— or —O—C( ⁇ O)—).
• R 4a is preferably a monovalent organic group structure including a fluorine atom of Formula (5) below, a mono(trifluoromethyl)phenyl group, or a bis(trifluoromethyl)phenyl group.
• W 1 and W 2 are the same or different and are each a hydrogen atom, a fluorine atom, a trifluoromethyl group, a difluoromethyl group, or a monofluoromethyl group; three w 3 s are each independently a hydrogen atom, a fluorine atom, or a combination of the hydrogen atom and the fluorine atom; at least one of W 1 , W 2 , and w 3 is a trifluoromethyl group, a difluoromethyl group, a monofluoromethyl group, or a fluorine atom; m2 is an integer of 0 to 9; and the maximum number of carbon atoms included in Formula (5) is 10.
• Formula (5) are Formula (5-1) to Formula (5-20).
• the unit structure of Formula (4) is added in order to improve the resist shape control and/or the solubility of the polymer (P) in the ether-based solvent. It has been found that, in particular, in the case of negative resists, secondary electrons to be generated from the side chain of R 4a due to radiation of EUV light are effective in the resist shape control.
• the unit structure of Formula (4) includes fluorine atoms, and fluorine atoms are known to absorb EUV light. It is therefore undesirable that the polymer (P) includes a high proportion of the unit structure of Formula (4).
• the molar ratio of Formula (4) to the entire polymer (P) is 0.1 to 40 mol %, preferably 0.1 to 30 mol %, further preferably 0.1 to 20 mol %, and further preferably 0.1 to 10 mol %, with respect to the entire polymer (P).
• the polymer (P) preferably further includes the unit structures of Formula (3) and Formula (4), if necessary, for the reason as described above, in addition to Formula (1) and Formula (2).
• a method for producing the polymer (P) used in the present invention includes the step of reacting compounds of Formula (1-a) and Formula (2-a), preferably, in proportions of:
• R 1 , R 2 , X 1 , X 2 , R 1 , n1, and m1 are as described above.
• Specific examples of the preferable compound of Formula (1-a) include Formula (1-1) to Formula (1-33).
• Specific examples of the preferable compound of Formula (2-a) include Formula (2-1) to Formula (2-4).
• the method for producing the polymer (P) includes the step of reacting a compound of Formula (1-a) and Formula (2-a), and further a compound of Formula (3-a) or/and Formula (4-a), if necessary, preferably in proportions of:
• R 3 , R 4 , X 3 , X 4 , R 3a , and R 4a the definitions of R 3 , R 4 , X 3 , X 4 , R 3a , and R 4a , and the preferable ranges are as described above.
• Specific examples of the preferable compound of Formula (3-a) include Formula (3-1) to Formula (3-20).
• Specific examples of the preferable compound of Formula (4-a) include Formula (4-1) to Formula (4-11).
• the polymer (P) can be synthesized by radical polymerization, anionic polymerization, cationic polymerization, or other methods, which are known methods for synthesizing acrylic polymers or methacrylic polymers. In this method, a variety of methods including known methods of solution polymerization, suspension polymerization, emulsion polymerization, and mass polymerization can be employed.
• polymerization initiator examples include 2,2′-azobis(isobutyronitrile), 2,2′-azobis(2-methylbutyronitrile), 2,2′-azobis(2,4-dimethylvaleronitrile), 4,4′-azobis(4-cyanovaleric acid), 2,2′-azobis(2,4-dimethylvaleronitrile), 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis(isobutyronitrile), 1,1′-azobis(cyclohexane-1-carbonitrile), 1-[(1-cyano-1-methylethyl)azo]formamide, 2,2′-azobis[2-(2-imidazoline-2-yl)propane]dihydrochloride, 2,2′-azobis[2-(2-imidazoline-2-yl)propane], and 2,2′-azobis(2-methylpropionamidine)dihydrochloride.
• Examples of the solvent for use in polymerization include dioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol propyl ether acetate, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxyprop
• Ethyl lactate is preferably used as the solvent for reaction of the polymer (P) in the composition according to the present invention.
• a stirring reaction is performed under reaction conditions of 50° C. to 200° C. for 1 hour to 48 hours to yield the polymer (P) used in the present invention.
• the solution including the polymer (P) thus obtained can be used as it is in preparation of the resist overlayer film forming composition.
• the polymer (P) may be precipitated and isolated in a poor solvent such as methanol, ethanol, ethyl acetate, hexane, toluene, acetonitrile, and water, or a solvent mixture thereof, and collected therefrom to be used.
• a water/methanol mixed solvent is preferably used as the solvent for precipitation of the polymer (P) to be used in the present invention.
• the polymer (P) may be re-dissolved as it is in the solvent to be used in the composition according to the present invention, or may be dried to be used.
• the preferable drying conditions are 30° C. to 100° C. for 6 to 48 hours in an oven or the like.
• the polymer (P) may be re-dissolved in the ether-based solvent and prepared as the composition according to the present invention, and can be used as the resist overlayer film forming composition.
• the weight average molecular weight of the polymer (P) to be used in the present invention as determined by gel permeation chromatography (GPC) is, for example, 500 to 2,000 in terms of polystyrene, although it varies depending on the solvent to be used, the solution viscosity, and the like.
• the weight average molecular weight is 500 or less, the polymer (P) may diffuse into the photoresist to deteriorate the lithography performance.
• the weight average molecular weight is 2,000 or more, the solubility in the ether solvent is insufficient, and stable composition according to the present invention cannot be formed.
• the solubility of the resist overlayer film to be formed in a photoresist developer is also insufficient to cause residue after development to be formed or to result in poor development (the pattern fails to be formed due to the left film).
• the content of the polymer (P) in the solid content in the composition is 20% by mass or more, for example 20 to 100% by mass, or 30 to 100% by mass.
• the solid content of the composition according to the present invention is 0.1 to 50% by mass, preferably 0.3 to 30% by mass.
• the solid content is obtained by removing the solvent component from the resist overlayer film forming composition.
• composition of the present invention may further include an acid compound, a basic compound, a surfactant, a rheology control agent, and other substances.
• the resist overlayer film forming composition of the present invention may further include an acid compound in order to match the acidity with that of the underlying resist in the lithography process.
• An acid compound in order to match the acidity with that of the underlying resist in the lithography process.
• a sulfonic acid compound or a sulfonic acid ester compound may be used as the acid compound.
• an acid compound such as bis(4-hydroxyphenyl) sulfone, p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium p-toluenesulfonic acid, salicylic acid, sulfosalicylic acid, citric acid, benzoic acid, and hydroxybenzoic acid, and/or a thermal acid generator such as 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, and 2-nitrobenzyl tosylate.
• the amount to be blended is 0.02% to 10% by mass, preferably 0.04% to 5% by mass relative to 100% by mass of the total solid content.
• the resist overlayer film forming composition of the present invention may include an acid generator that generates an acid by exposure light (for example, ArF excimer laser radiation, EUV radiation, and electron beam radiation) in order to match the acidity to that of the underlying resist in the lithography process.
• an acid generator that generates an acid by exposure light (for example, ArF excimer laser radiation, EUV radiation, and electron beam radiation) in order to match the acidity to that of the underlying resist in the lithography process.
• the acid generator include: onium salt-based acid generators such as bis(4-tert-butylphenyl)iodonium trifluoromethanesulfonate and triphenylsulfonium trifluoromethanesulfonate; halogen-containing compound-based acid generators such as phenyl-bis(trichloromethyl)-s-triazine; and sulfonic acid-based acid generators such as benzoin tosylate and N-hydroxysuccinimide trifluoromethanesulfonate.
• the amount of the acid generator to be added is 0.02% to 10% by mass and preferably 0.04% to 5% by mass relative to 100% by mass of the total solid content.
• the resist overlayer film forming composition of the present invention may include a basic compound.
• the basic compound is added to enable sensitivity to be controlled during exposure of the resist. That is, the basic compound such as amine reacts with acids generated by a photo acid generator during exposure to reduce the sensitivity of the resist underlayer film, so that the shape of the top portion of the resist after exposure development can be controlled (the resist after exposure and development is preferably rectangular).
• Examples of the basic compound include the known amine compounds described below.
• amine compounds include ammonia, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, 2-(dimethylamino)ethanol, 2,2,2-trifluoroethylamine, and 4-methylmorpholine.
• Another example is an aminobenzene compound of Formula (13-1).
• U 1 to U 5 each are a hydrogen atom, a C 1-10 alkyl group, or an amino group.
• Examples of the C 1-10 alkyl group include the above-described alkyl group, and preferred examples include methyl group, ethyl group, or isopropyl group.
• Examples of the compound are, for example, Formula (13-2) to Formula (13-47).
• Examples include tertiary amines such as triethanolamine, tributanolamine, trimethylamine, triethylamine, trinormalpropylamine, triisopropylamine, trinormalbutylamine, tri-tert-butylamine, trinormaloctylamine, triisopropanolamine, phenyldiethanolamine, stearyldiethanolamine, and diazabicyclooctane, and aromatic amines such as pyridine and 4-dimethylaminopyridine.
• Other examples include primary amines such as benzylamine and normalbutylamine, and secondary amines such as diethylamine and dinormalbutylamine. These compounds may be used singly or in combination of two or more of them.
• composition of the present invention may further include a rheology control agent, a surfactant, or other additives as necessary in addition to the above compounds.
• the rheology control agent is added mainly in order to improve flowability of the composition of the present invention.
• Specific examples include: phthalic acid derivatives such as dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dihexyl phthalate, and butyl isodecyl phthalate; adipic acid derivatives such as di-n-butyl adipate, diisobutyl adipate, diisooctyl adipate, and octyl decyl adipate; maleic acid derivatives such as di-n-butyl maleate, diethyl maleate, and dinonyl maleate; oleic acid derivatives such as methyl oleate, butyl oleate, and tetrahydrofurfuryl oleate; and stearic acid derivatives such as n-butyl stearate and glyceryl stearate.
• the ratio of these rheology control agents to be blended is generally less than 30% by mass with respect to 100% by mass of the total composition of the composition of the present invention.
• the composition of the present invention may further include a surfactant in order not to generate pinholes, striations, and other defects and to further improve the coating properties against surface irregularities.
• the surfactant include: nonionic surfactants including polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether, polyoxyethylene alkylallyl ethers such as polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether, polyoxyethylene/polyoxypropylene block copolymers, sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, and sorbitan tristearate, and polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene
• the amount of these surfactants to be blended is generally not more than 0.2% by mass and preferably not more than 0.1% by mass relative to 100% by mass of the total composition of the composition of the present invention.
• These surfactants may be added singly or in combination of two or more of them.
• the resist overlayer film forming composition according to the present invention can be produced by mixing the polymer (P) and a C 8-16 ether compound as a solvent according to the composition, for example, mixing with stirring at room temperature to 40° C.
• the resist to be used with the composition according to the present invention may be any of those for KrF (wavelength 248 nm), ArF (wavelength 193 nm), EUV (wavelength 13.5 nm), or electron beams (EB).
• the resists for EUV (wavelength 13.5 nm) and electron beams (EB) are preferable, and the resist for EUV (wavelength 13.5 nm) is further preferable.
• the composition according to the present invention has the excellent effects such as reducing OOB, improving lithography performance of the resist, and reducing outgas, as described above.
• the EUV resist to be applied underneath the resist overlayer film in the present invention may be either negative or positive.
• Examples include: a chemically amplified resist including an acid generator and a binder having a group that is decomposed by an acid to change the alkali dissolution rate; a chemically amplified resist including an alkali soluble binder, an acid generator, and a low molecular compound that is decomposed by an acid to change the alkali dissolution rate of the resist; a chemically amplified resist including an acid generator, a binder having a group that is decomposed by an acid to change the alkali dissolution rate, and a low molecular compound that is decomposed by an acid to change the alkali dissolution rate of the resist; a non-chemically amplified resist including a binder having a group that is decomposed by EUV to change the alkali dissolution rate; and a non-chemically amplified resist including a binder having a moiety that is cleaved by EU
• EUV resist materials examples include methacrylate-based materials, PHS-based materials, and hybrid materials containing both methacrylate and hydroxystyrene (HS).
• a KrF resist or an ArF resist can be used.
• the KrF resist or the ArF resist to be applied under the resist overlayer film in the present invention may be either a negative photoresist or a positive photoresist.
• the resist include a positive photoresist including a novolac resin and 1,2-naphthoquinonediazidesulfonic acid ester, a chemically amplified photoresist including a binder having a group that is decomposed by acids to increase the alkali dissolution rate and a photo acid generator, a chemically amplified photoresist including a low molecular weight compound that is decomposed by acids to increase the alkali dissolution rate of the photoresist, an alkali soluble binder, and a photo acid generator, and a chemically amplified photoresist including a binder having a group decomposed by acids to increase the alkali dissolution rate, a low molecular weight compound decomposed by acids to increase
• Examples include the trade name APEX-E manufactured by The Dow Chemical Company (ex-Rohm and Haas Electronic Materials), the trade name PAR710 manufactured by Sumitomo Chemical Industry Co., Ltd., and the trade name SEPR430 manufactured by Shin-Etsu Chemical Co., Ltd.
• Another example is a fluorine atom-containing polymer-based photoresist, for example, as described in ProC. SPIE, Vol. 3999, 330-334 (2000), ProC. SPIE, Vol. 3999, 357-364 (2000), and ProC. SPIE, Vol. 399), 365-374 (2000).
• an EB (electron beam) resist can be used.
• the electron beam resist to be applied under the resist overlayer film in the present invention may be either a negative photoresist or a positive photoresist.
• the resist include a chemically amplified resist including an acid generator and a binder having a group that is decomposed by acids to change the alkali dissolution rate, a chemically amplified resist including an alkali soluble binder, an acid generator, and a low molecular weight compound that is decomposed by acids to change the alkali dissolution rate of the resist, a chemically amplified resist including an acid generator, a binder having a group decomposed by acids to change the alkali dissolution rate, and a low molecular weight compound that is decomposed by acids to change the alkali dissolution rate of the resist, a non-chemically amplified resist including a binder having a group that is decomposed by electron beams to change the alkali dissolution rate, and a
• Examples of the developer for a positive resist having a resist overlayer film formed of the resist overlayer film forming composition of the present invention include aqueous solutions of alkalis including: inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia; primary amines such as ethylamine and N-propylamine; secondary amines such as diethylamine and di-N-butylamine; tertiary amines such as triethylamine and methyldiethylamine; alcohol amines such as dimethylethanolamine and triethanolamine; quaternary ammonium salts such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, and choline; and cyclic amines such as pyrrole and piperidine.
• inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium
• the aqueous solutions of alkalis may contain alcohols such as isopropyl alcohol or a surfactant such as a nonionic surfactant in an appropriate amount to be used.
• alcohols such as isopropyl alcohol or a surfactant such as a nonionic surfactant in an appropriate amount to be used.
• surfactant such as a nonionic surfactant
• quaternary ammonium salts are preferred, and tetramethylammonium hydroxide and choline are more preferred.
• a method for producing a semiconductor device of the present invention including the resist overlayer film forming composition of the present invention will be described below.
• a method for producing a semiconductor device can be used, for example, which includes: forming an EUV resist film on a substrate having a target film onto which a transfer pattern is to be formed, with or without an EUV resist underlayer film; applying the EUV resist overlayer film forming composition according to the present invention onto the resist film and baking the composition to form an EUV resist overlayer film; exposing the semiconductor substrate covered with the resist overlayer film and the resist film; and performing development after exposure to remove the resist overlayer film and the resist film.
• the exposure is performed with EUV light (at a wavelength of 13.5 nm).
• Producing the resist overlayer film is generally performed by spin coating in the same manner as in formation of a resist film.
• a substrate to be processed for example, a silicon/silicon dioxide-coated substrate, a glass substrate, or an ITO substrate
• a resist film is formed on the substrate to be processed
• the resist overlayer film forming composition (varnish) is applied on the substrate with a spin rate of 200 rpm to 3000 rpm, for example, followed by baking on a hot plate at 50° C. to 150° C. for 30 to 300 seconds to form the resist overlayer film.
• the thickness of the resist overlayer film formed is 3 nm to 100 nm, 5 nm to 100 nm, or 5 nm to 50 nm.
• the dissolution rate of the resist overlayer film to be formed in a photoresist developer is 1 nm or more per second, preferably 3 nm or more per second, more preferably 10 nm or more per second. If the dissolution rate is smaller than those values, the time required for removing the resist overlayer film is increased, resulting in lower productivity. After that, by pattern formation with appropriate exposure light followed by development using a resist developer to remove unnecessary parts of the resist and the resist overlayer film, a resist pattern is formed.
• the substrate to be processed of the semiconductor device can be processed either by a dry etching process or a wet etching process.
• the good resist pattern to be formed by using the resist overlayer film can be used as a mask to transfer a pattern with a good shape on the substrate to be processed by dry etching or wet etching.
• a method for producing a semiconductor device can be used, for example, which includes: forming a KrF resist film on a substrate having a target film onto which a transfer pattern is to be formed, with or without a KrF resist underlayer film; applying a KrF resist overlayer film forming composition according to the present invention on the resist film and baking the composition to form a KrF resist overlayer film; exposing the semiconductor substrate covered with the resist overlayer film and the resist film; and performing development after exposure to remove the resist overlayer film and the resist film. The exposure is performed with KrF.
• the resist overlayer film is formed in the same manner as in the EUV exposure.
• a method for producing a semiconductor device can be used, for example, which includes: forming an ArF resist film on a substrate having a target film onto which a transfer pattern is to be formed, with or without an ArF resist underlayer film; applying an ArF resist overlayer film forming composition according to the present invention on the resist film and baking the composition to form an ArF resist overlayer film; exposing the semiconductor substrate covered with the resist overlayer film and the resist film; and performing development after exposure to remove the resist overlayer film and the resist film. The exposure is performed with ArF.
• the resist overlayer film is formed in the same manner as in the EUV exposure.
• a method for producing a semiconductor device can be used, for example, which includes: forming an electron beam resist film on a substrate having a target film onto which a transfer pattern is to be formed, with or without an electron beam (EB) resist underlayer film; applying an electron beam resist overlayer film forming composition according to the present invention on the resist film and baking the composition to form an electron beam resist overlayer film; exposing the semiconductor substrate covered with the resist overlayer film and the resist film; and performing development after exposure to remove the resist overlayer film and the resist film. The exposure is performed with electron beams.
• the resist overlayer film is formed in the same manner as in the EUV exposure.
• a method for forming a resist pattern includes: forming an EUV resist film on a substrate having a target film for processing onto which a transfer pattern is to be formed, with or without an EUV resist underlayer film; applying the EUV resist overlayer film forming composition according to the present invention onto the resist film and baking the composition to form an EUV resist overlayer film; exposing the semiconductor substrate covered with the resist overlayer film and the resist film; and performing development after exposure to remove the resist overlayer film and the resist film. The exposure is performed with EUV.
• the resist overlayer film is generally formed by spin coating in the same manner as in formation of a resist film.
• a substrate to be processed for example, a silicon/silicon dioxide-coated substrate, a glass substrate, or an ITO substrate
• a resist film is formed on the substrate to be processed
• the resist overlayer film forming composition varnish
• the thickness of the resist overlayer film formed is 3 nm to 100 nm, 5 nm to 100 nm, or 5 nm to 50 nm.
• the dissolution rate of the resist overlayer film to be formed in a photoresist developer is 1 nm or more per second, preferably 3 nm or more per second, more preferably 10 nm or more per second. If the dissolution rate is smaller than these values, the time required for removing the resist overlayer film is increased, resulting in lower productivity. After that, by pattern formation with appropriate exposure light, followed by development using a resist developer to remove unnecessary parts of the resist and the resist overlayer film, a resist pattern is formed.
• the exposure wavelengths may be KrF, ArF, or electron beams (EB), with the resists for KrF, ArF, or electron beams (EB) respectively.
• the weight average molecular weights (Mw) of the polymers (P) shown in Synthesis Example 1 to Synthesis Example 10 and Comparative Synthesis Example 1 to Comparative Synthesis Example 6 in the present description were measured by Gel Permeation Chromatography (GPC). In the measurement, a GPC apparatus manufactured by TOSOH CORPORATION was used under the measurement conditions below. The degree of distribution shown in each synthesis example below in the present description is calculated from the measured weight average molecular weight and number average molecular weight.
• Measurement device HLC-8020GPC [trade name] (manufactured by TOSOH CORPORATION)
• GPC column TSKgel G2000HXL (two pillars), G3000HXL (one pillar), G4000HXL (one pillar) [trade name] (all manufactured by TOSOH CORPORATION), Column temperature: 40° C.
• This reaction solution was precipitated in 2,000 g of a water/methanol mixed solvent, and the resultant white solid was filtered off and then dried under reduced pressure at 40° C. overnight to yield the white polymer (P-1).
• This polymer (P-1) was subjected to GPC analysis, and the weight average molecular weight was 1,200 in terms of standard polystyrene. Presumably, the polymer (P-1) has the structure of Formula (p-1).
• the polymer (P-5) has the structure of Formula (p-15).
• An EUV resist solution (hydroxystyrene (HS)-containing resist) was applied using a spinner.
• the solution was heated on a hot plate at 100° C. for one minute to form a resist film, and the film thickness was measured.
• HS hydroxystyrene
• the degree of film loss of the resist was determined as shown in Table 1.
• the state in which almost no film loss is found is shown by ⁇ , and the state in which the film loss is found, which poses no problem in practice, is shown by ⁇ .
• resist overlayer film forming composition solutions prepared in Example 1 to Example 9 of the present invention and Comparative Example 1 and Comparative Example 2 were each applied on the wafer using a spinner and heated on a hot plate at 100° C. for one minute to form a resist overlayer film, and the film thickness was measured (film thickness A: the film thicknesses of the resist overlayer film).
• a puddle of a commercially available alkaline developer (manufactured by TOKYO OHKA KOGYO CO., LTD., product name: NMD-3) was formed on the resist overlayer film and left for 60 seconds, followed by rinsing with pure water for 30 seconds while being rotated at 3000 rpm. After rinsing, baking was performed at 100° C. for 60 seconds, and the film thickness was measured (film thickness B). If film thickness B is 0 nm, it can be said that the resist overlayer film was able to be removed by the developer.
• composition of the present invention is applicable as a resist overlayer film for a PTD process (Table 2).
• resist overlayer film forming composition solutions prepared in Example 1 to Example 10 of the present invention and Comparative Example 3 were each applied on a wafer using a spinner and heated on a hot plate at 100° C. for one minute to form a resist overlayer film, and the film thickness was measured (film thickness A: the film thickness of the resist overlayer film).
• the resist overlayer film forming composition solutions prepared in Example 1 to Example 10 of the present invention and Comparative Example 4 to Comparative Example 6 were each applied on a quartz substrate using a spinner. Each of the solutions was heated on a hot plate at 70° C. for one minute to form a resist overlayer film (film thickness of 30 nm). For these ten resist overlayer films, the absorptance at wavelengths of 200 nm to 260 nm was measured using a spectrophotometer. The transmissivity at 13.5 nm was calculated by simulation based on the relation between the element composition ratio and the film density.
• the property of blocking DUV light is considered to be good if the largest value of absorptance is 65% or higher and to be poor if lower than 65%, in a wavelength band of 200 nm to 260 nm.
• the transmittance of EUV light (13.5 nm) is considered to be good if the transmissivity is 80% or higher and to be poor if lower than 80%.
• the resist overlayer film obtained from the resist overlayer film forming composition in each Example is superior in blocking DUV light to the resist overlayer film obtained from the resist overlayer film forming composition of Comparative Example 4 and Comparative Example 5 and in transmittance of EUV light to the resist overlayer film obtained from the resist overlayer film forming composition of Comparative Example 6 (Table 4).
• An EUV resist solution was applied on a silicon wafer using a spinner and heated on a hot plate for one minute to form a resist film having a film thickness of 60 nm.
• the resist overlayer film forming composition solution prepared in Example 2 of the present invention was applied on the resist film using a spinner and heated on a hot plate at 70° C. for one minute to form a resist overlayer film having a film thickness of 10 nm.
• This silicon wafer was subjected to outgas analysis using a resist outgas monitor (EUV-PER1314 manufactured by EUV Technology) (Test Example 1).
• the silicon wafer on which a resist overlayer film was not formed was prepared as Test Example 2.
• An EUV resist solution that generates more outgas than that of usual patterning was used.
• An EUV resist solution was applied on a silicon wafer using a spinner and heated on a hot plate for one minute to form a resist film having a film thickness of 50 nm.
• EUV Micro Exposure Tool MS-13
• the target line width of the resist pattern to be formed was set to a line and space of 26 nm, and the Line Width Roughness (LWR) was compared by observing the resist pattern with optimum exposure amount and focus position (Test Examples 3 to 6).
• the silicon wafer on which no resist overlayer film was formed was prepared as Test Example 6.
• the resist overlayer film obtained from the resist overlayer film forming composition of Example was applied as a resist film overlayer, the LWR was significantly improved compared with the comparative example in which no resist overlayer film was applied. This indicates that the composition according to the present invention is used suitably for forming a resist pattern (Table 6).
• the composition of the present invention is a composition for forming an EUV resist overlayer film for use in an EUV lithography process or a resist overlayer film for a lithography process in other exposure wavelengths, which does not intermix with a resist, blocks undesirable exposure light, for example, UV and DUV and selectively transmits EUV alone, for example, in EUV exposure, and can be developed with a developer after exposure.

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